Download or read book The Influences of Changing Precipitation and Grazing Management on Sierra Nevada Mountain Meadow Plant Community Attributes and Function written by Matthew Ryan Freitas and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Domestic livestock grazing on mountain meadows of the Sierra Nevada is highly controversial and has been associated with negative effects on meadow species and function. In light of these effects, the US Forest Service has implemented policy and grazing management changes over the last 20 years, including the Sierra Nevada Forest Plan Amendment, which offered increased restrictions on grazing and protection for endangered meadow species. Here we ask how policy-driven changes in grazing management and precipitation have influenced trends in plant community characteristics and function in high elevation meadows. We surveyed long-term monitoring sites on 30 meadows across 12 US Forest Service grazing allotments at approximately five-year intervals from 1999 to 2010. During the study period there were significant increases in species richness and diversity, but no significant changes in species evenness and soil stability provided by the plant community. Whether the site was grazed was not significantly correlated to changes in any of the plant community metrics, but precipitation and the frequency of perennial grasslike species were negatively related to species richness and diversity. The effects of precipitation on species evenness and soil stability were dependent upon site type, with the wettest meadow sites showing greater decreases in species evenness and increases in soil stability with increasing precipitation. These findings suggest that the current levels of grazing pressure, as enforced under the Sierra Nevada Forest Plan Amendment are not hindering the dynamics of mountain meadow plant communities. In the projected climate scenarios of a longer and drier growing season in the Sierra Nevada, the implications of the relationships between precipitation and meadow plant community attributes and function will likely become more important to the management of these systems. As species diversity and evenness appear to be oppositely related to changes in precipitation from soil stability, managers may increasingly have to balance goals for these contrasting indicators of meadow health.